In California, those with influence have secured water for agriculture at below market rates, water delivered with infrastructure built by taxpayer dollars.
When people can get a resource for less than the cost of delivering it, they use it with less discretion. And the prices of the things they produce with it don't reflect the true value of the water, even if they did pay for all costs of delivery.
That's because water has value itself. Its not just the cost of delivering it that matters.
But when a resource is allocated with a political process, the only costs that are considered are the costs of delivery. Assuming the taxpayer's interests are represented at all.
The political process is notoriously shortsighted. But if someone owns a resource, they have an interest in preserving it. Its sale price represents the total future value of it, not just what can be extracted during a politicians term of office.
Private ownership is not the cause of all of the political wars over water. It is their solution.